Nepenthes adnata /nɪˈpɛnθiːz ædˈnɑːtə/ is a tropical pitcher plant endemic to the Indonesian province of West Sumatra, where it grows at elevations of 600 to 1200 m above sea level.

[note a] The holotype, Meijer 6941, was collected on that date near the river Tjampo, east of Payakumbuh, Taram, West Sumatra, at an elevation of 1000 m. It is deposited at the National Herbarium of the Netherlands in Leiden.

[3] The species was first described in 1986 by Mitsuru Hotta and Rusjdi Tamin based on specimens the authors collected near Harau in West Sumatra.

[3] The peristome is roughly symmetrical in cross section, with the inner portion accounting for around 54% of its total cross-sectional surface length.

[3][10] In its natural habitat, the species occurs sympatrically with N. tenuis and grows in close proximity to N. albomarginata, N. ampullaria, N. eustachya, N. gracilis, N. longifolia, and N. reinwardtiana.

[3][8] In Kelok Sembilan, the species has been found to grow alongside Utricularia striatula, a distantly related carnivorous plant.

[3] Only two collections of this species have been made and these correspond to two populations separated by several kilometres of mountainous terrain.

The species may be more widespread in the region, but most cliffs in the Tjampo river area are virtually inaccessible by foot, making the discovery of new localities unlikely in the near future.

The habitat of this species may be threatened in the near future by fires deliberately started to clear forest for agricultural purposes.

Rusjdi Tamin and Mitsuru Hotta considered the species to be closely related to N. tentaculata, N. gracillima, and N. gracilis.

[4] Both Jan Schlauer and Joachim Nerz[2] as well as Matthew Jebb and Martin Cheek[5] agreed that N. adnata and N. tentaculata are related, while J. H. Adam, C. C. Wilcock and M. D. Swaine considered the two taxa conspecific.

"[3] Clarke points out that the multicellular hairs sometimes exhibited by N.adnata, which several authors have used to suggest a relationship with N. tentaculata, occur in rosette pitchers of many other species, especially N. rafflesiana.

[3] Seedlings of N. adnata and N. longifolia are virtually indistinguishable, although mature plants have few morphological features in common.

[3] In 2001, Clarke performed a cladistic analysis of the Nepenthes species of Sumatra and Peninsular Malaysia using 70 morphological characteristics of each taxon.